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import logging
import os
import pathlib
import django.contrib.auth.models as amodels
import rrdtool
from django.conf import settings
from django.db import models
log = logging.getLogger(__name__)
def _sanitize_path(path):
# changing all separators to a _ should result in an ugly filename
# that will not cause issues.
# an additional _ is added at the beginning to prevent hidden files
for sep in os.sep, os.altsep:
if sep:
path = path.replace(sep, "_")
return "_" + path
class ModelWithPerms(models.Model):
users_read = models.ManyToManyField(
amodels.User,
related_name="%(class)s_read",
blank=True,
)
users_write = models.ManyToManyField(
amodels.User,
related_name="%(class)s_write",
blank=True,
)
groups_read = models.ManyToManyField(
amodels.Group,
related_name="%(class)s_read",
blank=True,
)
groups_write = models.ManyToManyField(
amodels.Group,
related_name="%(class)s_write",
blank=True,
)
class Meta:
abstract = True
class DataSource(ModelWithPerms):
# an mqtt topic can be as long as 65,535 bytes when UTF-8 encoded,
# which is probably too much for a sensible db
topic = models.CharField(max_length=512)
path = models.CharField(
max_length=512,
)
rrd_config = models.TextField(
default=settings.RRD_DS_CONFIG
)
active = models.BooleanField(
default=True,
)
def __str__(self):
return self.topic
@property
def rrd_path(self):
path = os.path.abspath(os.path.join(
settings.RRD_DB_PATH, self.path
))
base_path = os.path.abspath(settings.RRD_DB_PATH)
if pathlib.Path(base_path) not in pathlib.Path(path).parents:
return os.path.abspath(os.path.join(
settings.RRD_DB_PATH,
_sanitize_path(self.path)
))
return path
@property
def ds_name(self):
return self.topic.split("/")[-1]
@property
def lastupdate(self):
try:
last = rrdtool.lastupdate(self.rrd_path)
except rrdtool.OperationalError as e:
log.warning("Failure reading from ds: %s", e)
return (None, None)
else:
return last["date"], last["ds"][self.ds_name]
def update(self, ts, value):
if not os.path.isfile(self.rrd_path):
rrdtool.create(
self.rrd_path,
"--no-overwrite",
self.rrd_config.format(
ds_name=self.ds_name
).strip().split('\n'),
)
try:
rrdtool.update(
self.rrd_path,
str(ts) + ":" + str(value)
)
except ValueError as e:
log.warning("Could not update ds: %s", e)
for graph in self.graph_set.all():
graph.update()
class Graph(ModelWithPerms):
title = models.CharField(max_length=64)
data_sources = models.ManyToManyField(DataSource)
path = models.CharField(
max_length=512,
)
rrd_config = models.TextField(
default=settings.RRD_GRAPH_CONFIG
)
def __str__(self):
return self.title
@property
def graph_path(self):
path = os.path.abspath(os.path.join(
settings.RRD_GRAPH_PATH, self.path
))
base_path = os.path.abspath(settings.RRD_GRAPH_PATH)
if pathlib.Path(base_path) not in pathlib.Path(path).parents:
return os.path.abspath(os.path.join(
settings.RRD_GRAPH_PATH,
_sanitize_path(self.path)
))
return path
def update(self):
graph_path = self.graph_path
os.makedirs(os.path.dirname(graph_path), exist_ok=True)
rrd_paths = []
rrd_topics = []
rrd_ds_names = []
for ds in self.data_sources.all():
rrd_paths.append(ds.rrd_path)
rrd_topics.append(ds.topic)
rrd_ds_names.append(ds.ds_name)
opts = self.rrd_config.format(
topics=rrd_topics,
ds_names=rrd_ds_names,
ds_paths=rrd_paths,
title=self.title,
).strip().split('\n')
opts = [o.strip() for o in opts]
rrdtool.graph(
graph_path,
* opts
)
class Dashboard(ModelWithPerms):
title = models.CharField(max_length=64)
graphs = models.ManyToManyField(Graph)
data_sources = models.ManyToManyField(DataSource)
template = models.TextField()
def __str__(self):
return self.title
|
